|
Cervical
incompetence is painless cervical dilation resulting in delivery
of a live fetus between 16 and 22 wk. Ultrasonography during the
2nd trimester may help assess risk. Treatment is reinforcing the
cervical ring with suture material (cerclage).
In women with weak cervical tissue, the enlarging products of conception cause the cervix to dilate prematurely. Weakness may be congenital (eg, in Ehlers-Danlos syndrome) or secondary to cone biopsies (particularly when ≥ 1.7 to 2.0 cm of the cervix is removed), deep cervical lacerations, or previous excessive dilation with instruments. Additional risk factors include müllerian duct defects (eg, bicornuate or septate uterus), induction of ovulation (which often results in multifetal pregnancy), and ≥ 3 prior fetal losses during the 2nd trimester. Overall risk of recurrence of cervical incompetence is probably ≤ 30%. Risk is greatest for women with ≥ 3 prior 2nd-trimester fetal losses.
Diagnosis
and Treatment
Cervical incompetence is diagnosed clinically. The increased use of routine second trimester transvaginal ultrasound has documented an inverse relationship between cervical length and preterm delivery; cervical shortening on ultrasound to < 2 cm is considered a risk factor.
Cerclage (reinforcement of the cervical ring with suture material) appears to prevent preterm delivery in patients with ≥ 3 prior 2nd-trimester fetal losses. For other patients, the procedure should probably be limited to those with a history suggesting cervical incompetence plus ultrasound demonstration of cervical shortening prior to 22 to 24 wk gestation; restricting cerclage to such patients does not appear to increase risk of preterm delivery and reduces the number of cerclages currently being done by 2⁄3. Evidence does not support use of cerclage simply for ultrasound-detected cervical shortening.
Last full review/revision November 2005
Content last modified November 2005
| 
